The double portrait, by John Keane, shows an unusually stern and contemplative Snow; in the background is a blurred rendering of him as he appears on television, complete with tie. Channel 4 has lent it for four months to the portrait gallery.

Snow's career in journalism began in 1973 as a reporter for Independent Radio News. In 1976 he moved to ITN, where he served as diplomatic editor and Washington correspondent. He has been the anchorman for Channel 4 News since 1989, while continuing to report on major news stories.

He won a Bafta in 2005, and was named Journalist of the Year in 2006 by the Royal Television Society.

The artist John Keane worked as a waiter and domestic cleaner. The territory he has explored in his career as a painter has often overlapped with Snow's own, and he was the official war artist in the 1991 Gulf war. His portraits of the late Mo Mowlam and the trade unionist Bill Morris are part of the NPG permanent collection.

The director of the gallery, Sandy Nairne, said: "Jon Snow by John Keane brings a much loved figure from television into the world of art, to striking effect."